BBC: Sichuan 2008: A disaster on an immense scale
In terms of the energy released, the Magnitude 7.9 earthquake that struck Sichuan province in China in May 2008 was not a record-setter. But the destruction it wrought, and the number of people it affected, certainly make it a stand-out event.
The impact of the Sichuan quake was not only felt through the death toll and significant economic loss but also in terms of the sheer number of people affected.
It was mid-afternoon, when school and university classes were being taught, office workers had returned to their desks from lunch, and the Sichuan working day was in full swing.
Eighty kilometres away (50 miles) from the 7.6-million-person megacity of Chengdu, 19km under the Earth, the fault began to rupture. The fault broke over a length of 240km.